.back-to-main {
    text-align: center;
    margin-top: 20px;
}

.back-to-main .back-btn {
    display: inline-block;
    padding: 10px 20px;
    font-size: 14px;
    font-weight: bold;
    color: white;
    background-color: #4A90E2;
    border: none;
    border-radius: 4px;
    text-decoration: none;
    transition: background-color 0.3s ease;
}

.back-to-main .back-btn:hover {
    background-color: #357ABD;
}

.back-btn {
    display: inline-block;
    padding: 10px 20px;
    font-size: 14px;
    font-weight: bold;
    color: white;
    background-color: #4A90E2;
    border: none;
    border-radius: 4px;
    text-decoration: none;
    transition: background-color 0.3s ease;
    background-color: #357ABD;
}

.back-btn:hover {
    background-color: #357ABD;
}

/* 查询表单 */
.search-group {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 20px;
}

.search-group label {
    font-weight: bold;
}

.search-group input, .search-group select {
    padding: 5px;
    border: 1px solid #ddd;
    border-radius: 4px;
}

.search-btn {
    padding: 5px 10px;
    background-color: #4A90E2;
    color: white;
    border: none;
    border-radius: 4px;
    cursor: pointer;
}

.search-btn:hover {
    background-color: #357ABD;
}

/* 课程表 */
.course-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 20px;
}

.course-table th, .course-table td {
    border: 1px solid #ddd;
    padding: 10px;
    text-align: center;
}

.course-table th {
    background-color: #f4f4f4;
    font-weight: bold;
}

.course-image {
    display: block;
    margin-top: 5px;
    max-width: 100px;
    height: auto;
    border: 1px solid #ddd;
    border-radius: 4px;
}

/* 操作按钮 */
.edit-btn, .delete-btn {
    padding: 5px 10px;
    margin: 2px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
}

.edit-btn {
    background-color: #4CAF50;
    color: white;
}

.edit-btn:hover {
    background-color: #45A049;
}

.delete-btn {
    background-color: #E74C3C;
    color: white;
}

.delete-btn:hover {
    background-color: #C0392B;
}